The overall objectives continue to be the resolution of the mitochondrial oxidative phosphorylation system and reconstitution of the activity with the resolved purified components. Such reconstitution with a minimum number of components would provide unequivocal evidence for the detailed molecular mechanism of energy transduction in mammalian cells. Current approach also includes attempts to reassemble a minimal membrane from the oligomycin sensitive ATPase (OS-ATPase) and purified fractions of known function.